Kinetic studies for the production of tertiary ethers used as gasoline additives

Boz, Nezahat
In the present study, the kinetics studies for etherification reactions were investigated in detail. In the first phase of present study, different acidic resin catalysts were prepared by the heat treatment of Amberlyst-15 catalysts at 220°C at different durations of time and also by the synthesis of sulfonated styrene divinylbenzene cross-linked resins at different conditions. A linear dependence of reaction rate on hydrogen ion-exchange capacity was in 2M2B+ethanol reaction. However, in the case of 2M1B+ethanol reaction hydrogen ion-exchange capacities over 2.8 meq.H+/g did not cause further increase in reaction rate, which was concluded to be majorly due to significance of diffusional resistances. DRIFTS experiments carried out with alcohols, isobutylene, isoamylenes and TAME (tert-amyl-methyl-ether) in a temperature range of 333-353 K supported a Langmuir-Hinshelwood type reaction mechanism involving adsorbed isoolefins molecules forming a bridged structure between اSO3H sites of the catalyst and adsorbed alcohol molecules. A rate expression derived basing on the mechanism proposed from the DRIFTS results gave good agreement with the published data. Reaction rate was found to give a sharp maximum at ethanol activity of around 0.1. The third phase of this work included evaluation of effective diffusivities and adsorption equilibrium constants of methanol, ethanol and 2M2B, in Amberlyst-15 from moment analysis of batch adsorber dynamic results. Models proposed for monodisperse and bidisperse pore structures were used for the evaluation of effective diffusivities. It was shown that surface diffusion contribution was quite significant. In the last phase of the work, a batch Reflux-Recycle-Reactor (RRR) was proposed, modeled and constructed to achieve high yields and selectivities in equilibrium limited reactions. The batch reflux recycle reactor was modeled by


Dynamic and steady-state analysis of oxidative dehydrogenation of ethane
Karamullaoğlu, Gülsün; Doğu, Timur; Department of Chemical Engineering (2005)
In this research, oxidative dehydrogenation of ethane to ethylene was studied over Cr-O and Cr-V-O mixed oxide catalysts through steady-state and dynamic experiments. The catalysts were prepared by the complexation method. By XRD, presence of Cr2O3 phase in Cr-O; and the small Cr2O3 and V2O4 phases of Cr-V-O were revealed. In H2-TPR, both catalysts showed reduction behaviour. From XPS the likely presence of Cr+6 on fresh Cr-O was found. On Cr-V-O, the possible reduction of V+5 and Cr+6 forms of the fresh sa...
Comparison of Fenitrothion and Trifluralin Adsorption on Organo-Zeolites and Activated Carbon. Part II: Thermodynamic Parameters and the Suitability of the Kinetic Models of Pesticide Adsorption
LÜLE ŞENÖZ, Güzide Meltem; Atalay, Mustafa Ümit (Informa UK Limited, 2014-07-04)
The suitability of two kinetic models and the thermodynamic parameters of pesticide adsorption were investigated based on obtained data of previous studies. Kinetic evaluation indicated that the pesticides adsorption on adsorbents followed the pseudo-second-order model. Gibbs free energy (Delta G degrees), enthalpy (Delta H degrees), and entropy (Delta S degrees) were calculated for thermodynamic parameters by using linearized Arrhenius equation. The results indicated that the sorption process of fenitrothi...
Experimental investagation of drag reduction effects of polymer additives on turbulent pipe flow
Zeybek, Şerife; Uludağ, Yusuf; Department of Chemical Engineering (2005)
Since the discovery of the drag reduction effects of even small amount of macromolecules in solutions in turbulent pipe flows, there have been many experimental and theoretical studies in order to understand mechanisms behind this phenomenon. Theories have been proposed based on the observations on the change in the characteristics of the turbulent flow near the pipe wall where friction of the momentum transfer between the flow and the conduit takes place. In this study drag reduction in fully developed tur...
Structure sensitivity of selective co oxidation over precious metal catalysts
Atalık, Bora; Üner, Deniz; Department of Chemical Engineering (2005)
In this study, the effect of Pt particle size on the reaction rate and selectivity of preferential oxidation of CO (PROX) reaction was investigated on Pt/Al2O3. 2% Pt/?-Al2O3 catalysts were prepared by incipient wetness method; the particle size of the catalysts was modified by calcination temperature and duration. Therefore, the relative amounts of low and high coordination atoms on the metal particle surface can be changed. Over these catalysts, first, the CO oxidation reaction was studied in the absence ...
Study of Sorption of Alcohols on High Silica ZSM-35
Babuçcuoğlu, Yurdaer; Yücel, Hayrettin; Department of Chemical Engineering (2007)
This study investigated the equilibrium sorption capacities and rates of sorption of some alcohols on Na- and/or H- form of ZSM-35 at different temperatures by gravimetric method using an electrobalance. The alcohols studied were methanol, ethanol, propan-1-ol, propan-2-ol, n-butanol. The ZSM-35 sample used in sorption experiments resulted from a study for synthesis of high silica ZSM-35 zeolite. This ZSM-35 sample was called as NaZSM-35. The influence of ion-exchange on the sorption capacity and kinetics w...
Citation Formats
N. Boz, “Kinetic studies for the production of tertiary ethers used as gasoline additives,” Ph.D. - Doctoral Program, Middle East Technical University, 2004.